Commission 30. Radial Velocities (Vitesses Radiales)

Extract

A new generation of major redshift surveys, with numbers of redshifts that far surpass those of earlier investigations, is getting under way. These surveys make use of fibre optics, but differ from earlier systems in that often hundreds - not just tens - of galaxies can be observed simultaneously, by means of improved fibre management techniques. One of the most prominent is the Sloan Digital Survey (63.013.080) which aims to provide photometry and redshifts for a million galaxies, using a dedicated 2.5 m telescope that is soon to commence operations. The Two-degree Field instrument on the 3.9 m Anglo-Australian Telescope (63.031.120) will have up to 400 fibres per field - while one field is being exposed, a robot will work on positioning a further 400 fibres, ready for the next exposure. Similarly the DENIS (63.036.281) and 2MASS surveys, mapping in the near-infrared, will require very large numbers of follow-up redshifts. Also, in terms of new technology, the 8.5 m Hobby-Eberly Telescope, a dedicated spectroscopic telescope, is soon to see first light; its low-resolution spectrograph should be able to service galaxies down to V = 23.5.